Initial import of the CDE 2.1.30 sources from the Open Group.

cde/lib/DtSearch/raima/recprev.c

@@ -0,0 +1,126 @@
+/* $XConsortium: recprev.c /main/2 1996/05/09 04:15:00 drk $ */
+/*
+ *   COMPONENT_NAME: austext
+ *
+ *   FUNCTIONS: d_recprev
+ *
+ *   ORIGINS: 157
+ *
+ *   OBJECT CODE ONLY SOURCE MATERIALS
+ */
+/*-----------------------------------------------------------------------
+
+   recprev.c - scan database backwards via database address
+
+   d_recprev is used to scan the database backwards via the database address.
+   It is the compliment to recnext.  It is generally called after d_reclast.
+
+   AUTHOR:  R.S. Carlson
+   DATE:    06-Jul-88
+   PROJECT: db_VISTA 3.10
+
+   Copyright (C) 1988 by Raima Corporation
+
+-----------------------------------------------------------------------*/
+
+/* ********************** EDIT HISTORY *******************************
+
+ SCR    DATE    INI                   DESCRIPTION
+----- --------- --- -----------------------------------------------------
+  351 06-Jul-88 RSC added new function to runtime
+      04-Aug-88 RTK MULTI_TASK changes
+      18-Aug-88 RSC moved rn_type/dba to separate table.
+      17-Oct-88 RSC changed return to RETURN
+
+*/
+
+
+/* ********************** INCLUDE FILES ****************************** */
+
+#include <stdio.h>
+#include "vista.h"
+#include "dbtype.h"
+
+/* ********************** GLOBAL VARIABLE DECLARATIONS *************** */
+/* ********************** GLOBAL FUNCTION DECLARATIONS *************** */
+/* ********************** EXTERNAL VARIABLE DECLARATIONS ************* */
+/* ********************** EXTERNAL FUNCTION DECLARATIONS ************* */
+/* ********************** LOCAL VARIABLE DECLARATIONS **************** */
+/* ********************** LOCAL FUNCTION DECLARATIONS **************** */
+
+/* ======================================================================
+   d_recprev - find previous record via database address
+*/
+int d_recprev( TASK_DBN_ONLY )
+TASK_DECL
+DBN_DECL
+{
+/*
+   RETURNS: db_status.  Also sets current record to previous matched record.
+   ASSUMES: nothing.
+*/
+   DB_ADDR dba;			/* current database addr we're scanning */
+   FILE_NO fno;			/* current file we're scanning */
+   F_ADDR last;			/* last slot in file */
+   int rec_ndx;			/* index of RECORD ENTRY (not used) */
+   char FAR *recptr;		/* record from database */
+   RECORD_ENTRY FAR *rec_ptr;	/* RECORD ENTRY for this record */
+   INT rectype;			/* record type from record */
+   F_ADDR rno;			/* current slot we're scanning */
+   FILE_NO ft;			/* normalized file */
+
+#ifndef SINGLE_USER
+   int dbopen_sv;		/* saved copy of dbopen */
+#endif
+
+   DB_ENTER(DB_ID TASK_ID LOCK_SET(RECORD_IO));
+
+   /* setup current record and file number */
+   if ( RN_REF(rn_type) < 0) RETURN( dberr(S_NOTYPE) );
+   if ( RN_REF(rn_dba) ) {
+      fno = (FILE_NO)((RN_REF(rn_dba) >> FILESHIFT) & FILEMASK);
+      rno = RN_REF(rn_dba) & ADDRMASK;
+   }
+   else {		/* no current rec, get fno from rn_type */
+      nrec_check(RN_REF(rn_type) + RECMARK, &rec_ndx, (RECORD_ENTRY FAR * FAR *)&rec_ptr);
+      fno = NUM2EXT(rec_ptr->rt_file, ft_offset);
+      fno = (int)((fno >> FILESHIFT) & FILEMASK);
+
+      /* compute rno as last slot in file */
+      if ( (last = dio_pznext(rec_ptr->rt_file)) <= 0 )
+         RETURN( db_status );
+
+      rno = last;
+   }
+   ft = NUM2INT( fno, ft_offset );
+   
+   /* scan backwards looking for a record of the same type */
+   rno--;
+   do {
+      if (rno < 1) RETURN( db_status = S_NOTFOUND );
+      dba = ((fno & FILEMASK) << FILESHIFT) | (rno & ADDRMASK);
+#ifndef SINGLE_USER
+      dbopen_sv = dbopen;
+      dbopen = 2;		/* setup to allow for unlocked read */
+#endif
+      dio_read(dba, (char FAR * FAR *)&recptr, NOPGHOLD);
+#ifndef SINGLE_USER
+      dbopen = dbopen_sv;
+#endif
+      if (db_status != S_OKAY) RETURN( db_status );
+
+      /* see if we've found a match */
+      bytecpy(&rectype, recptr, sizeof(INT));
+#ifndef SINGLE_USER
+      rectype &= ~((INT)RLBMASK);
+#endif
+      rno--;
+   } while ( rectype != RN_REF(rn_type) );
+
+   /* when we get here, we know a match was found */
+   curr_rec = dba;		/* set current record to match */
+   RN_REF(rn_type) = rectype;
+   RN_REF(rn_dba) = dba;
+   RETURN( db_status = S_OKAY );
+}
+/* vpp -nOS2 -dUNIX -nBSD -nVANILLA_BSD -nVMS -nMEMLOCK -nWINDOWS -nFAR_ALLOC -f/usr/users/master/config/nonwin recprev.c */